Cementitious compositions and methods

ABSTRACT

1. A COMPOSITION OF MATTER WHICH COMPRISES A LIQUID SLURRY OF (A) FROM ABOUT 0.1 TO ABOUT 2 PARTS BY WEIGHT OF A WATER-SOLUBLE CARBAMOLY POLYMER PER PART BY WEIGHT OF A LIQUID, GEL FORMING ORGANO SOLVENT THEREFORE COMPOSED; OF A LIQUID ORGANIC NON-SOLVENT FOR THE POLYMER SELECTED FROM THE GROUP CONSISTING OF PROPYLENE GLYCOL, WATER-,ISCIBLE ALKYLENE OXIDE POLYMERS HAVING MOLECULAR WEIGHT UP TO ABOUT 600 AND WATER-MISCIBLE ALKYL AND ARYL ETHERS OF THE POLYMERS WHEREIN THE ETHERIFYING MOIETY CONTAINS FROM 1 TO 12 CARBONS AND (B) AT LEAST ABOUT 0.05 PART BY WEIGHT PER PART BY WEIGHT OF THE NON-SOLVENT, OF AN ORGANIC SOLVENT FOR THE POLYMER, THE AMOUNT OF THE LATTER BEING SUFFICIENT TO RENDER THE LIQUID MIXTURE A SOLVENT FOR THE POLYMER, SAID ORGANIC SOLVENT BEING PENTAERYTHRITOL.

United States Patent CEMENTITIOUS COMPOSITIONS AND METHODS Louis H.Eilers, Inola, and Christ F. Parks, Tulsa, Okla., assignors to The DowChemical Company, Midland, Mich.

No Drawing. Application July 12, 1971, Ser. No. 161,875,

now Patent No. 3,746,725, which is a continuation-inpart of applicationSer. No. 17,290, Mar. 6, 1970, now Patent No. 3,624,018, which in turnis a continuation of application Ser. No. 486,530, Sept. 10, 1965, nowPatent No. 3,511,313. Divided and this application Nov. 21, 1972, Ser.No. 308,490

Int. Cl. C08f 45/34 U.S. Cl. 26033.2 R 6 Claims ABSTRACT OF THEDISCLOSURE The sealing of void spaces, e.g. as in geological formationsand/or between metal shapes is accomplished with a liquid slurry of aparticulate, water-soluble organic polymer in an organo solvent. Themixture of the polymer and solvent has a controlled set time to allowthe emplacement of the slurry as a liquid. The slurry then sets to forma sealing cementitious material.

CROSS-REFERENCE TO RELATED APPLICATION This is a division of applicationSer. No. 161,875, filed July 12, 1971 now Pat. 3,746,725 which in turnis a continuation-in-part of application Ser. No. 17,290, filed Mar. 6,1970 now Pat. No. 3,624,018 and application Ser. No. 486,530, filedSept. 10, 1965, now Pat. No. 3,511,313.

The present invention provides a novel approach to a variety ofcementing needs. It is particularly beneficial for use in geologicalformations. The formulations described herein set to hard gels ofexcellent strength properties and with adhesion to a large number ofsubstrates. Control of the set times of the cementitious formulationspermits convenient application of the compositions as readily flowableliquids. Particular uses of the gels include sealing oil well boreholes,cementing well casings to adjacent formations and coating geologicalformations to render them impermeable to fluids.

In general, the method of the invention comprises applying to void spacedefined by solid surfaces a liquid slurry of a particulate,water-soluble, organic polymer and an organo solvent therefor andmaintaining the liquid mixture in such void space until it has hardenedinto a shape retaining gel, i.e., set.

The terminology water-soluble organic polymer as used herein refers tononionic, anionic, cationic or ampholytic organic materials composed ofa number of repeating units or mers. The useful polymers arecharacterized by dispersibility in water to form visually continuoussolution or dispersions. This includes truly watersoluble polymers whichdisperse in water to provide homogeneous, transparent solutions subjectto water dilution without phase separation. Also included within themeaning of water-soluble, as used herein, are the water-swellablepolymers which readily disperse in Water to produce a highly disperseand visually continuous system of individually distinct, gel particles.

Organo solvents useful in the invention fall into three general classes.Each class is characterized by unique gel forming characteristics and inthe properties of the final hardened gel. Although the organo solventused may consist of only organic materials it may also be mixed withwater, or, in fact, any desired liquid material compatible with thesolvent to produce a variation within the invention. As used herein theterm organo solvent refers to a homogeneous liquid composedsubstantially of an organic material, that is, it contains no more thanabout 50 percent by weight of water, which organo solvent is absorbed bythe particulate polymer to form a continuous phase.

The first class of organo solvents useful in the invention, hereinaftertermed Group I solvents, are the liquid organic solvents which solvateor plasticize solid, watersoluble polymers. That is, the polymers, ifthey are not totally miscible with the solvent, absorb a significantproportion of the same. Solvents of this nature, suitable for use with awide variety of water-soluble polymers, include for example ethyleneglycol, ethylenediamine, glycerol, dioxolane, formamide,pentaery'thritol and acetic acid. Some materials may not function assolvents at normal room temperatures but can be activated as solventsfor most water-soluble polymers at elevated temperatures. Such materialsinclude diethylene glycol, dipropylene glycol, diethanol amine,monoethanol amine, propylene glycol, triethylene glycol,diethylenetriamine and triethanolamine.

A second class of useful organo solvents, hereinafter termed Group IIsolvents, includes a large number of organic materials which are notsolvents for the polymers (non-solvents), i.e., they do not solvate orplasticize the water-soluble polymers to form a continuous phase, but

which, when mixed with a small amount of water, produce organo solventsuseful for the purpose of the invention. Manifestly, such materials mustbe miscible with water. It has been found that as little as 1 percent byweight water dissolved in an organic liquid, which is not a solvent forthe polymer, often renders the resulting mixture a suitable organosolvent for the purposes of the invention. Sometimes the organicmaterial may normally exist as a solid. In such instances, enough water,e.g., up to 50 percent by weight of the total solvent composition may beused to provide a liquid solution of the organic material. The resultingaqueous solution is an organo solvent suitable for the purposes of theinvention. Since the set time of a formulation is decreased by increasesin the water content of the organo solvent used, the amount of water isusually maintained at less than about 25 percent by weight of the totalsolvent composition.

Materials which are not normally solvents for the water-solublepolymers, but which on addition of water become such solvents at roomtemperature, e.g., F., include diethylene glycol, dipropylene glycol,diethylene glycol monomethylether, ethylene glycol monoethylether,dioxane, ethylene carbonate, ethanolamine, triethylene glycol, propyleneglycol, sucrose, urea, dextrin, diethanol amine, triethanol amine, anddiethylene triamine. A most useful class of organic materials forformulating Group II solvents includes the liquid alkylene oxidepolymers, which are not solvents in themselves for the water-solublepolymers. Such alkylene oxide polymers include, in addition to thosementioned above, higher polymers of ethylene oxide having molecularweights up to as much as 600 or so. Liquid propylene oxide polymersinclude tripropylene glycol, tetrapropylene glycol and higher propyleneoxide polymers having molecular weights up to as much as 1200 or so. Inaddition, water-soluble alkyl and aryl monoethers of the alkylene oxidepolymers can form useful solvents when mixed with water. Exemplary alkyland aryl etherifying groups include methyl, ethyl, propyl, butyl,dodecyl, phenyl, butylphenyl and the like groups.

A third class of organo solvents, hereinafter termed Group III solvents,is composed of mutual solutions of an organic material, which is notsolvent for the watersoluble polymers, and an organic material, which isa solvent for the polymer, i.e., a Group I solvent. In such mixtures, atleast about 0.05 part of the polymer solvent is employed for each partby weight of the non-solvent. Such organo solvents allow convenientadjustment of the set times in non-aqueous cementitious formulations byincreasing or decreasing the amount of polymer solvent relative to thenon-solvent.

Controlling the set times, or in other words gel times, of water-solublepolymer-solvent mixtures, wherein the organo solvent classifies withGroup I solvents, is achieved through temperature control. Thetemperature of the polymer-solvent mixture is decreased to a point atwhich gelation occurs after a given period of time as the temperature ofthe system equilibrates with its environment. The formulationtemperatures is most conveniently controlled by adjusting thetemperature of the organo solvent.

In some instances, a cementitious formulation requires temperatureshigher than room temperature in order to achieve a set. Examples of suchsolvents operable as the sole solvent only at higher temperatures havebeen described hereinbefore. Illustratively, diethylene glycol,propylene glycol and dipropylene glycol and diethanol amine areeffective if utilized at temperatures above about 100 F. Formulationsprepared with such organo solvents are most useful, with their longshelf lives, for grouting and scaling subterranean geological formationswhich normally exist at temperatures above 100 F. or so.

The set times of formulations prepared with Group II solvents can beadjusted by the proportion of water incorporated into the organicmaterials which are non-solvents for the polymers, As little as 0.5% byweight water, based on the total organo solvent, will appreciablyshorten the set time of the formulation. Unless the polymer nonsolventrequires a higher proportion of water to exist as a liquid, it isgenerally not desirable in the interest of providing longer set times toutilize more than 25% by weight Water based on the weight of the totalorgano solvent.

The set times of formulations prepared with Group III solvents arecontrolled by the proportion of organic polymer solvent utilizedconjunctively with the organic, polymer non-solvent. With increases inthe amount of solvent in relation to the non-solvent, the set time isdecreased. Organo solvents of this type are preferred for use inapplications where control of set times cannot be achieved by control oftemperature and a non-aqueous cement is desired.

The water-soluble, particulate organic polymers useful herein areavailable in a wide variety of chemical compositions. They may beobtained as natural polymeric products, by modification of naturalpolymers or by synthesis from polymerizable materials.

Water solubility is imparted to such polymers by the presence in andalong the polymer chain of a number of hydrophilic moieties sufiicientto more than offset the otherwise hydrophobic character of the organicpolymer. One class of such hydrophilic moieties includes the ioniz ablegroups. Among these are the sulfate and sulfonate groups, carboxylatesalt groups, amino and ammonium groups, the latter being inclusive ofprotonated as well as quaternary derivatives of the amines, e.g., mono-,diand trialkyl substituted ammonium salt groups, and phosphoric acidgroups and monoand dibasic salts thereof. Whenever acid salts arereferred to, those generally intended are the alkali metal, alkalineearth metal (water-soluble species thereof) and ammonium salts.

Another class of water-solubility imparting, hydrophilic moieties aresuch non-ionizable groups as carboxamide, and monoand dialkylN-substituted carboxamides, having a total of up to about 8 carbons.Also of a hydrophilic nature, though less strongly than some of theaforementioned groups are, hydroxyl, acetal, ketal, carbamate and lactamgroups. In any event, the polymers employed herein contain one or moreof the aforedescribed hydrophilic moieties, and the like, in and alongthe polymer chain in a sufiicient amount to render the resulting polymerwater-soluble as defined above.

The polymers used in the invention are characterized by a high molecularweight. An adequate molecular weight is shown if the polymer can beobtained as a particulate solid and a 2 percent by weight solution ofthe polymer in water, at a pH of 7, has a viscosity, measured with aBrookfiield Viscosimeter at 25 C., of at least 10 centipoises.

Technology for preparing the water-soluble polymers useful herein isknown. Useful ethylenically polymerized polymers are described inHedrick et al., U.S. Pat. 2,625,- 529, Aimone et al., U.S. Pat.2,740,522 and Booth et al., U.S. Pat. 2,729,557. A variety ofwater-soluble polysaccharide derivatives are described in Gloor, U.S.Pat. 2,728,725. Water-soluble polyurethanes or chain extended polyolsare taught in Honea et al., U.S. Pat. 3,054,778 and a variety ofpolycarbamates and polylactams in Hibbard et al., U.S. Pat. 3,044,992,Walles et al., U.S. Pat. 2,946,772, Vitales U.S. Pat. 2,874,124, andFong et al., U.S. Pat. 3,000,830. These are to mention but a few of thewell-known chemical avenues for the preparation of watersolubleparticulate macromolecules. Further general descriptions of a variety ofwater-soluble, particulate maroomolecules is contained in Davidson andSittig Water- Soluble Resins, Reinhold Publishing Corp., New York, 1962.

Preferred for use herein are Water-soluble carbamoyl polymers. The mostcommon forms of these are ethylenically polymerized polymers havingattached along their polyalkane backbone a plurality of carbamoyl groupsaccording to the formula:

wherein R and R are independently selected from the group of hydrogenand alkyl hydrocarbons with 1 to 4 carbons.

In particular, useful carbamoyl polymers include the variouswater-soluble homopolymers and copolymers of acrylamide andmethacrylamide. Other carbamoyl polymers are the various water-solublecopolymers of N-substituted acrylamides such as N-methyl acrylamide,N-propyl acrylamide and N-butyl acrylamide. Still other carbamoylpolymers are prepared from the amides and half amides of maleic andfumaric acids. In general, any ethylenically unsaturated andpolymerizable monomer, which contains the carbamoyl group, may beemployed in the preparation of the preferred carbamoyl polymers.

Best results are obtained, if at least about 25 mole percent of thepolymerized mers have carbamoyl substituents. The balance of thecomonomers used to prepare the copolymers can be provided in the form ofany Watersoluble, or water-insoluble, monoethylenically monomercopolymerizable therewith, so long as the total amount of water-solublemonomers used is sufficient to impart water-solubility to the finishedpolymer.

Other water-soluble polymers useful herein are the lightly cross-linkedwater-swellable polymers. Such crosslinking can be achieved byirradiation of linear, watersoluble polymers under conditions whichpromote crosslinking or by incorporating a small amount, e.g., up to 1%by weight, of a polyfunctional monomer into the polymerization recipefor a linear water-soluble polymer. Examples of such monomers, which maybe copolymerized with monoethylenically unsaturated monomers, aremethylenebisacrylamide, divinylbenzene, divinylether, divinylether ofethylene glycol and the like.

In preparing the cementitious gels of the invention, it is best to addthe polymeric ingredient to the organo solvent. The organo solvent isprepared first, if there is more than one material involved, to providea uniform liquid medium. If temperature is to be relied upon to controlthe set time, the organo solvent is adjusted to a desired temperature.Subsequently, a particulate form of the water-soluble, solid organicpolymer is incorporated into the liquid mixture. The mixture is suppliedwith sufficient agitation to suspend or slurry the polymer in the organo'solverit .The resulting liquid slurry is then placed in the "void tobe-sealed. Ultimately theslurry produces a shape 7 retaining gel whichtenaciously adheres to its solid environm'ent'. i

The strength of thefinal set composition is controlled in part by theamount of the polymer used. Useful strength propertiesare often achievedby incorporating into-the organo solvent at leastabout 0.1 part byweight J of the polymer per part by weight of the solvent. In any 5event, .at'least enough of the polymer is used to achieve gellation ofthe composition. This can be insured by employing at least about 0.5part'by weight of the polymer per part by weight of the organo solvent.The upper limit "arpoiymer usage is controlled only by the need to provide a flowable liquid slurry. Generally, no more than about 2 parts byweight ofthe polymer per part by weight of the solvent are used.Mixing'of the ingredients is readily achieved using con- .ventional'solids-liquids mixing devices. Emplacement of the resulting fluidadmixture is achieved by any of the usual liquid slurry handling means.For instance, ordinary centrifugal pumps are satisfactory for pumpingthe slurry. If needed, the slurry is easily maintained in the void spacef to be sealed until, it sets by suitable confining forms and/ orsuitably applied fluid pressure.

'In a special embodiment'of the invention, the cementitious compositionof the invention has been discovered to be further enhanced with'respectto its properties, espe- -cially-its cohesive strength, by incorporatinginto the composition an oxide, hydroxide or salt of a polyvalent metal.Specific oxides, hydroxides and salts, all of which must .havesomesolubility, however slight, in the liquid phase, include those of'thefollowing metals: calcium, magnesium, zinc, ferric, aluminum and thelike. Useful salts in- 'clude the chlorides and sulfates of thesemetals. The use .of-from about 0.05 percent up to a maximum of about 12.percent based on the weight of the polymer-solvent composition, of oneor more of the aforementioned inorganic materials increasessubstantially the yield strengfl1 for cohesiveness of the finally setcementitious composi- ..tions of, the invention.

7 'When set, the formulations of the invention provide tough fluidbarriers with good adhesion to a wide variety of substrates,specifically including most geological forrnations, especially siliceousformations. Once set, the cementitious compositions of the invention arerelatively impervious to water. They will imbibe water when in confactwith aqueous media, but if confined, as within a formation or. well,casing, they will not lose their strength properties even afterprolonged contact with aqueous medial m The following examples providefurther illustration of the, invention.

Example 1 This example illustrates formulating cementitious gelsaccording to the invention using Group I and Group II organo solvents.To 100 milliliters of ethylene glycol at a temperature of F. was added75 grams of a particulate carbamoyl polymer. The polymer was apolyacrylamide in which about 7 percent of the initially avail ablecarboxamide groups had been hydrolyzed to sodium carboxylate groups. Itwas characterized by a molecular weight of at least about one million.The polymer was stirred into the ethylene glycol to produce a uniformblend at about 75 F. (approximate room temperature). The composition setto a shape retaining, rubbery gel in 45 minutes. 7

The set gel is useful as a cement in a variety of oil well treatingapplications. In a specific use, a slurry prepared as described above isplaced in the annulus defined by two concentric oil well casings. Whenset, the composition provides a highly adherent and persistent annularseal.

To illustrate set time control with Group III organo solvents, a secondformulation was prepared with a 50/50 mixture of ethylene glycol anddiethylene glycol, which are a solvent and non-solvent for the polymerrespectively. To milliliters of this mixture at 75 F. was added 75 gramsof the above polymer. After about 4 hours, the composition achieved aninitial set to produce a solid, rubbery cement. By way of comparison, 75grams of the polymer in 100 milliliters of diethylene glycol remainedfluid through 48 hours, after which the test was terminated.

Through the conjoint use of the non-solvent and solvent to prepare theorgano solvent, the set time of the composition was extended by over 3hours. The longer set time permits batchwise preparation of theformulation and otherwise more extensive handling thereof prior to use.

Example 2 pared with the Group III solvent was poured into a verticallyaligned pipe, the lower end of which was plugged with a ruber stopper.The composition was allowed to cure for about 20 hours at 75 F. In asecond run, the temperature was increased to C. In this manner, plugseals about 12 inches long were produced in each pipe. The set time ofthe composition at these temperatures was determined as the length oftime required for the organo solvent-polymer slurry to form a shaperetaining mass.

To measure seal quality, the upper end of the pipe was fitted with ahigh pressure cap and the rubber stopper removed. Nitrogen gas wasapplied gradually to the seal until it failed or withstood the maximumpressure for 10 minutes. The maximum pressure applied with thistechnique was 1,000 pounds per square inch.

In still further runs similar to the above, a series of compositionswere prepared in which portions of the polymer were replaced withcorresponding amounts of magnesium hydroxide. The curing and testingconditions were as discussed above.

The compositions, set times for cures at 75 F. and 150 F., and adhesionstrength properties for the above operations are included in thefollowing table:

e TAB LE 1 Properties Formulation .Set time (hrs.) Oarbamoyl EthyleneYield atpolymer, glycol, Diethylene Mg(OH) 2, strength,

gm. m glycol. m1. gm. p.s.i. 75 F. 150 F.

7 Example 3 Gel times for polymer-solvent mixtures of the invention wereascertained according to the procedure set forth in Section 9, Schedule6, of API-RP 10B, Twelfth Edi- '8 Example 4 I A series of formulationswas prepared in accordance with the invention using Group II solvents.The series illustrates the effect of increasing amounts of water ontion, March 1963. Basically, the procedure involved using 5 the set timeof the formulation. To 100 milliliters of a the thickening time testeras therein described. The test device was charged with a polymer-solventsystem to be tested. In these operations, the formulations were heatedto a maximum of 144 F. in 36 minutes during which time continuousviscosity measurements were made. Thickening or gellation set times weremeasured as the elapsed time between starting the heating of theformulation and particular organo solvent was added 60 grams of thepolyacrylamide used in Example 1. The aliquots of each formulation weremaintained at different temperatures ranging from 80 to 200 F. Theelapsed time from formulation of the polymer-solvent slurry until ahardened gel formed was measured and is reported in the following tableas the gel time.

TABLE 3 Weight pereetnt Gel time (hours) at specified temp. of-

wa er Organo solvent added 80 F. 100 F. 120 F. 150 F. 175 F. 200 F.

Dicthylene glycol... 48 14 3. 5 1. 5 Do 20 8 2 0.7

Do Dipropylene glycol.

Do Diethanol amine...

the occurrence of a slurry consistency of 100 poises. The thickeningtimes of several formulations are set forth in the following Table 2. 13

TABLE 2 Volume percent Tempera- Diethyltures at ene Ethylene Set time,time of glycol glycol mins. set F.)

Of the above runs, run number 3 is a preferred formulation foremployment in a well with a bottom hole temperature of 144 F. The settime of 49 minutes allows sufficient opportunity for placing thecomposition in the well prior to its setting and thus becomingunworkable.

Example 5 Although water-soluble carbamoyl polymers are preferred foruse in the invention, ,useful cementitious compositions can beformulated from any of a wide variety of other types of water-solubleorganic polymers. To illustrate the general applicability of theinvention, exemplary species of natural gums, natural proteins,polysaccharide derivatives, vinyl polymers other than carbamoylpolymers, polyurethanes and polyethylene Oxides were evaluated with eachof three organo solvents. All of the polymers tested, were characterizedby high molecular weights as hereinbefore defined. Representative ofGroup I solvents were ethylene glycol and ethanolamine. Representativeof Group II was a 66% by weight solution of sucrose in water.

The polymer being evaluated was added to 50 milliliters of the organosolvent in small increments until a definite increase in slurryviscosity was apparent. This amount of polymer was then mixed with 50milliliters of the solvent first at 80 F. and, if no set resulted within48 hours, again with the solvent at 150 F.

The amounts of polymer used to produce a gel and the temperature atwhich gelation was obtained are set forth in the following table alongwith the set time of the particular composition in hours.

TABLE 4 Ethylene glycol Monoethanol amine 66% sucrose in water PolymerSet Cure Polymer Set Cure Polymer Set Temp amt. time temp., amt timetemp., amt time Water-soluble polymers (gm.) (hours) F. (gm.) (hours) F.(gm.) (hours) 2s a as s as a s 3-: h el??? gum 80 31 1 NS 80 0. 1 150 1724 Gelatin 80 43 0. 25 80 38 0. 25 80 19 4 I Corn starch 80 3 NS 49 0.25 26 I NB Carboxymethyl cellulose 80 37 4 150 28 I NS 80 17 0. 1 Sodiumpolystyrene sull'onate... 80 13 0. 1 80 33 0. 25 80 7 0. 25 PolyN-vinylpyrrolidone (water 80 25 0. 1 80 33 0.25 80 15 0. 25 Polyurethane 150 340.25 150 35 I NS 80 24 48 Polyethylene oxid 150 14 0.25 150 18 I NS 15013 24 Polyvinylalrnhol 150 18 2 NS 80 27 24 80 14 1 NSVinylacetate-maleic halfamide copolymer 80 39 0.5 80 35 I NS 150 15 24 1This is the reaction product of a polyglyeol of 10,000 average molecularweight and a small amount of toluene diisocyanate. 2 NS means notsatisfactory as the result of poor final properties e.g., the productcrumbles or there 15 no gel formation at all.

What is claimed is:

1. A composition of matter which comprises a liquid slurry of (a) fromabout 0.1 to about 2 parts by weight of a water-soluble carbamoylpolymer per part by weight of a liquid, gel forming organo solventtherefor composed of a liquid organic non-solvent for the polymerselected from the group consisting of propylene glycol, water-misciblealkylene oxide polymers having molecular weight up to about 600 andwater-miscible alkyl and aryl ethers of the polymers wherein theetherifying moiety contains from 1 to 12 carbons and (b) at least about0.05 part by weight per part by weight of the non-solvent, of an organicsolvent for the polymer, the amount of the latter being sufiicient torender the liquid mixture a solvent for the polymer, said organicsolvent being pentaerythritol.

2. A composition as in Claim 1 wherein the carbamoyl polymer is apolyacrylamide.

3. A composition as in Claim 1 wherein the carbamoyl is a styrenemaleamide copolymer.

4. A composition as in Claim 1 wherein the carbamoyl polymer ischaracterized by an ethylenically polymerized polyalkane backbone inwhich at least about 25 mole percent of the polymerized mers havesubstituent groups of the formula:

10 wherein R and R are independently selected from the group of hydrogenand alkyl hydrocarbons with 1 to 4 carbons.

5. A composition as in Claim 1 wherein the amount of organo solvent iscontrolled in relation to the organo nonsolvent to provide apredetermined set time.

6. A composition as in Claim 1 and including a finely divided solidoxide, hydroxide or a salt of a polyvalent metal.

References Cited UNITED STATES PATENTS 3,746,725 7/1973 Eilers 26033.4 R3,511,313 5/1970 Eilers 26032.6 MX 3,493,529 2/1970 Krottinger 26029.62,961,044 11/1960 Shell 16621 ALLAN LIEBERMAN, Primary Examiner R.ZAITLEN, Assistant Examiner U.S. C1. X.R. 26033.4 R

1. A COMPOSITION OF MATTER WHICH COMPRISES A LIQUID SLURRY OF (A) FROMABOUT 0.1 TO ABOUT 2 PARTS BY WEIGHT OF A WATER-SOLUBLE CARBAMOLYPOLYMER PER PART BY WEIGHT OF A LIQUID, GEL FORMING ORGANO SOLVENTTHEREFORE COMPOSED; OF A LIQUID ORGANIC NON-SOLVENT FOR THE POLYMERSELECTED FROM THE GROUP CONSISTING OF PROPYLENE GLYCOL, WATER-,ISCIBLEALKYLENE OXIDE POLYMERS HAVING MOLECULAR WEIGHT UP TO ABOUT 600 ANDWATER-MISCIBLE ALKYL AND ARYL ETHERS OF THE POLYMERS WHEREIN THEETHERIFYING MOIETY CONTAINS FROM 1 TO 12 CARBONS AND (B) AT LEAST ABOUT0.05 PART BY WEIGHT PER PART BY WEIGHT OF THE NON-SOLVENT, OF AN ORGANICSOLVENT FOR THE POLYMER, THE AMOUNT OF THE LATTER BEING SUFFICIENT TORENDER THE LIQUID MIXTURE A SOLVENT FOR THE POLYMER, SAID ORGANICSOLVENT BEING PENTAERYTHRITOL.